Martin Dr. Kleen

Evaluation of magnetic navigation in an in vitro model of uterine artery embolization.

PURPOSE To compare steering of a novel magnetic guide wire with a standard 0.014-inch guide wire within a vascular phantom. MATERIALS AND METHODS The magnetic guiding system (MGS) was composed of two permanent magnets on each long side of the fluoroscopy table generating a 0.1-T magnetic field, and a C-arm angiography system. The magnetic field was created according to vectors drawn onto two radiographic projections. Consequently, the tip of the intravascular guide wire containing a permanent magnet was deflected parallel to the magnetic field. Ninety-six catheterizations were performed in water-filled polyvinyl chloride tubes imitating the arterial tree of a female pelvis. This vascular phantom resembled a total of 12 uterine arteries with three different calibers (inner diameters: 1.1 mm, 1.7 mm, and 4.2 mm). Fluoroscopy and procedure times were measured to compare magnetic-assisted and conventional catheterization. RESULTS Catheterization to every predefined target was successful for all attempts with both guiding techniques. The fluoroscopy time during magnetic navigation was significantly shorter in vessels of all three sizes compared with conventional navigation (means of 19.6 sec, 5.9 sec, and 4.8 sec vs. 48.8 sec, 49.8 sec, and 32.7 sec for small, medium, and large vessels, respectively; P < .05). Procedure times with use of the magnetic guide wire (149.6 sec, 52.1 sec, and 39.9 sec) were not significantly different than those with conventional navigation (60.4 sec, 68.6 sec, and 47.7 sec). CONCLUSIONS The MGS enables exact endovascular navigation with shorter fluoroscopy time in an in vitro model. The MGS may offer opportunities to reduce x-ray exposure to patients and staff.